In the related prior art, surgical operations using artificial blood vessels for treatments of an aortic aneurysm or aortic dissection have been performed, but a low invasive treatment using a stent graft has been widely performed in recent years (for example, see WO97/048350). A general stent graft is formed by suturing and fixing a skeleton (stent) in which a wire such as a nickel titanium alloy or stainless steel is formed in a Z shape or a ring shape to an inner surface or an outer surface of a tube (graft) which is formed of a cloth (fabric) woven by threads of a resin such as a polyester in a cylindrical shape, and is indwelled in a desired blood vessel by being deployed and expanded in a body cavity.
For example, in a case where a treatment for an aortic aneurysm is performed with a stent graft, it is required for both ends thereof to be indwelled in a normal blood vessel in the vicinity of a pathological blood vessel. Accordingly, a necessary minimum indwelling length required for a stent graft treatment becomes the length between normal blood vessels located in front and back of the pathological blood vessel. In general, the placement position or a necessary length of a stent graft is predicted from an X-ray contrast image or a CT image acquired before a surgery. But since it is difficult to predict the placement position or the necessary length, the predicted length does not always reach the necessary indwelling length and thus a new stent graft is required to be additionally inserted so that both of the ends thereof indwell in a blood vessel having a plurality of bent sections. Further, in a case where an aneurysm generated in a bent section of a blood vessel is treated with an indwelling stent graft, there is a possibility that the bent section in the blood vessel is distorted in a process of recovery and both of the ends of the indwelling stent graft fall out.
As a method for solving the above-described problem, it has been considered to use a stent graft which is longer than the necessary length for indwelling and to indwell the stent graft while it is being contracted in the length direction as needed. The stent graft is contracted and the entire length thereof is shortened by an operator pushing up the entire delivery device while gradually deploying the stent graft from the central side thereof by lowering a sheath accommodating the stent graft which is arranged on the outer surface of a shaft.
However, such a method depends on the expertise and/or technique of an operator, so there is a possibility that a graft is turned over or skeletons (frames) overlap each other when the degree of pushing up the delivery device is great, for example.